Videos captured by video cameras may suffer from a problem known as camera shake. For example, a video camera mounted at an area for, e.g., monitoring the area, may from time to time experience shakes or vibrations due to shifting environmental factors, such as wind, vehicles (e.g. airplanes, trains, trucks, etc.) entering or leaving the area, construction work, and the like. Such shakes or vibrations will induce movement of the video camera, thereby causing a captured video to shake.
Prior art systems for image stabilization to reduce the effects of camera shake often include electronic manipulation of a video captured by the video camera before displaying the video. By doing so, the viewer is presented with a stable view of the video despite the induced movement of the video camera.
A photograph or drawing whose edges gradually fade into the surrounding paper is called a vignette. The art of creating such an illustration is a deliberate one. Yet the word vignetting is also used to indicate an unintended darkening of the image corners in a photographic image or stream of images, i.e. a video. The unintended and undesired vignetting is an effect caused by lens, iris and/or image sensor limitations.
For videos wherein image stabilization is performed, vignetting can become annoying. This occurs since the image frames of the video will be shifted and/or cropped differently for different image frames in order to make the video look stable. Hence, after performing image stabilization an effect of vignetting shaking will be present in the video. Vignetting removal algorithms are readily available. If the vignetting is heavy however, removing it will heavily amplify noise in the affected areas.